Principles of Immunisation Flashcards
What are the 2 modes of acquiring immunity?
Active and Passive
What is the advantage of passive immunity?
It gives immediate protection
What are the disadvantages of passive immunity?
There is only a short term effect- no immunological memory
Serum sickness - incoming Ab is recognised as a foreign antigen
Incoming immune cells can reject the recipient
How is active immunisation acquired naturally?
Exposure/infection by the antigen
How is active immunity acquired artificially?
Vaccination
What is an antigen?
Whole organism or part of it which stimulates an immune response
Does an immunological memory produce an immediate effect?
No but it produces a faster and better response to the next antigenic encounter- secondary response
Give 2 difference between the primary and secondary exposure to an antigen?
Primary - low Ab conc.
Secondary - high Ab conc.
Primary - slower response
Secondary - faster response
Name 3 common diseases we vaccinate against?
Measles
Mumps
Rubella
What does the MMR vaccine vaccinate against?
Measles
Mumps
Rubella
What can the disease mumps lead to?
Meningitis
Who is rubella dangerous to?
Unborn children
Temporarily who are there restriction to vaccinations to?
Those with febrile illness
Those who are pregnant
Permanently who are there restrictions to vaccinations to?
Those with specific allergies
Those who are immunocompromised
What was the first vaccine made against?
Small pox
Is small pox eradicated?
Yes
What does a disease organism have that induces an immune response?
Antigens
What do antigens stimulate the production of?
Antibodies
Once antibodies have destructed the disease causing organism what are formed?
Memory B cells
Why can’t live, virulent organisms be used in vaccines?
They are too dangerous
They would induce the disease they are trying to prevent
Which vaccines carry the most risk?
Live attenuated vaccines
What are live attenuated vaccines?
A vaccine that contains the live organism that has been weakened
Why are live attenuated vaccines often the most successful?
Because they multiply in the body creating a large immune response
Explain inactivated vaccines
A vaccine that is produced by killing the disease causing microbe with radiation, heat or radiation
Why do inactivated vaccines often require several booster shots?
To maintain the persons immunity
Do inactivated vaccine produce a strong immune response?
No - they stimulate a weaker response
What do inactivated vaccines consist of?
Either killed organisms or purified fractions of the micro-organism
What is an acellular vaccine?
One that only uses the antigenic part of the disease causing organism
Do acellular vaccines often require a booster and if so why?
Yes because they generally don’t induce the strongest immune response
Can acellular vaccines cause the disease?
No
What is a toxoid vaccine?
Used when a bacterial toxin is the main cause of illness - when bacteria secrete toxins or harmful chemicals but the toxins are inactivate
How are the toxins inactivated in toxoid vaccines?
They are treated with formalin
After a toxin is treated to decrease its harmfulness what is it known as?
A toxoid
What is a subunit vaccine?
A vaccine that includes the antigen that best stimulates the immune system
What is an epitope?
The part of the antigen that the Ab or T cells recognsises
What is an adjuvant?
A substance which enhances the body’s immune response to an antigen
What is the adjuvant commonly used in humans?
Aluminium Salts
Why are aluminium salts used?
As they generally cause only mild inflammatory reactions they are safe and they have the ability to generate memory
What is the primary aim of vaccination?
To protect the individual receiving it
What is herd immunity?
When a large proportion of the population are vaccinated that is protects those who are not vaccinated
What does herd immunity reduce the risk of?
An unvaccinated individual being exposed to infection
What are some vaccines that should be given to travellers?
Hepatitis A Typhoid Cholera Rabies Yellow fever
